1. Related Technical Fields
Related technical fields include navigation systems, methods, and programs that determine a degree of difficulty of turning right or left at an intersection that vehicle is approaching.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2004-271375 discloses a navigation apparatus capable of providing information on a route. The route is selected depending on the number of times a vehicle has to change a lane to make a right/left turn at an intersection. In the navigation apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2004-271375, detection of the congestion degree of lanes is not performed.